1. Field of the Invention
This invention generally relates to a bicycle rear derailleur. More specifically, the present invention relates to a bicycle rear derailleur having a linkage moved by a motor unit.
2. Background Information
A bicycle typically uses a chain drive transmission for transmitting a pedaling force to a rear wheel. The chain drive transmission of a bicycle often uses derailleurs to selectively move a chain from one of a plurality of sprockets to another for changing speeds of the bicycle. A typical derailleur has a base member, a movable member supporting a chain guide and a linkage assembly (e.g., a moving mechanism) coupled between the base member and the movable member so that the chain guide moves laterally relative to the base member. Recently, derailleurs have been equipped with motor units to make shifting gears easier.